gdb/infcall.c - gdb

Global variables defined

Functions defined

Macros defined

Source code

  1. /* Perform an inferior function call, for GDB, the GNU debugger.

  3.    Copyright (C) 1986-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  7.    This program is free software; you can redistribute it and/or modify
  8.    it under the terms of the GNU General Public License as published by
  9.    the Free Software Foundation; either version 3 of the License, or
  10.    (at your option) any later version.

  12.    This program is distributed in the hope that it will be useful,
  13.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15.    GNU General Public License for more details.

  17.    You should have received a copy of the GNU General Public License
  18.    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

  20. #include "defs.h"
  21. #include "breakpoint.h"
  22. #include "tracepoint.h"
  23. #include "target.h"
  24. #include "regcache.h"
  25. #include "inferior.h"
  26. #include "infrun.h"
  27. #include "block.h"
  28. #include "gdbcore.h"
  29. #include "language.h"
  30. #include "objfiles.h"
  31. #include "gdbcmd.h"
  32. #include "command.h"
  33. #include "infcall.h"
  34. #include "dummy-frame.h"
  35. #include "ada-lang.h"
  36. #include "gdbthread.h"
  37. #include "event-top.h"
  38. #include "observer.h"

  40. /* If we can't find a function's name from its address,
  41.    we print this instead.  */
  42. ‌#define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
  43. ‌#define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
  44.                                    + 2 * sizeof (CORE_ADDR))

  46. /* NOTE: cagney/2003-04-16: What's the future of this code?

  48.    GDB needs an asynchronous expression evaluator, that means an
  49.    asynchronous inferior function call implementation, and that in
  50.    turn means restructuring the code so that it is event driven.  */

  52. /* How you should pass arguments to a function depends on whether it
  53.    was defined in K&R style or prototype style.  If you define a
  54.    function using the K&R syntax that takes a `float' argument, then
  55.    callers must pass that argument as a `double'.  If you define the
  56.    function using the prototype syntax, then you must pass the
  57.    argument as a `float', with no promotion.

  59.    Unfortunately, on certain older platforms, the debug info doesn't
  60.    indicate reliably how each function was defined.  A function type's
  61.    TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
  62.    defined in prototype style.  When calling a function whose
  63.    TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
  64.    decide what to do.

  66.    For modern targets, it is proper to assume that, if the prototype
  67.    flag is clear, that can be trusted: `float' arguments should be
  68.    promoted to `double'.  For some older targets, if the prototype
  69.    flag is clear, that doesn't tell us anything.  The default is to
  70.    trust the debug information; the user can override this behavior
  71.    with "set coerce-float-to-double 0".  */

  73. ‌static int coerce_float_to_double_p = 1;
  74. static void
  75. ‌show_coerce_float_to_double_p (struct ui_file *file, int from_tty,
  76.                                struct cmd_list_element *c, const char *value)
  77. {
  78.   fprintf_filtered (file,
  79.                     _("Coercion of floats to doubles "
  80.                       "when calling functions is %s.\n"),
  81.                     value);
  82. }

  84. /* This boolean tells what gdb should do if a signal is received while
  85.    in a function called from gdb (call dummy).  If set, gdb unwinds
  86.    the stack and restore the context to what as it was before the
  87.    call.

  89.    The default is to stop in the frame where the signal was received.  */

  91. ‌static int unwind_on_signal_p = 0;
  92. static void
  93. ‌show_unwind_on_signal_p (struct ui_file *file, int from_tty,
  94.                          struct cmd_list_element *c, const char *value)
  95. {
  96.   fprintf_filtered (file,
  97.                     _("Unwinding of stack if a signal is "
  98.                       "received while in a call dummy is %s.\n"),
  99.                     value);
  100. }

  102. /* This boolean tells what gdb should do if a std::terminate call is
  103.    made while in a function called from gdb (call dummy).
  104.    As the confines of a single dummy stack prohibit out-of-frame
  105.    handlers from handling a raised exception, and as out-of-frame
  106.    handlers are common in C++, this can lead to no handler being found
  107.    by the unwinder, and a std::terminate call.  This is a false positive.
  108.    If set, gdb unwinds the stack and restores the context to what it
  109.    was before the call.

  111.    The default is to unwind the frame if a std::terminate call is
  112.    made.  */

  114. ‌static int unwind_on_terminating_exception_p = 1;

  116. static void
  117. ‌show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty,
  118.                                         struct cmd_list_element *c,
  119.                                         const char *value)

  121. {
  122.   fprintf_filtered (file,
  123.                     _("Unwind stack if a C++ exception is "
  124.                       "unhandled while in a call dummy is %s.\n"),
  125.                     value);
  126. }

  128. /* Perform the standard coercions that are specified
  129.    for arguments to be passed to C or Ada functions.

  131.    If PARAM_TYPE is non-NULL, it is the expected parameter type.
  132.    IS_PROTOTYPED is non-zero if the function declaration is prototyped.
  133.    SP is the stack pointer were additional data can be pushed (updating
  134.    its value as needed).  */

  136. static struct value *
  137. ‌value_arg_coerce (struct gdbarch *gdbarch, struct value *arg,
  138.                   struct type *param_type, int is_prototyped, CORE_ADDR *sp)
  139. {
  140.   const struct builtin_type *builtin = builtin_type (gdbarch);
  141.   struct type *arg_type = check_typedef (value_type (arg));
  142.   struct type *type
  143.     = param_type ? check_typedef (param_type) : arg_type;

  145.   /* Perform any Ada-specific coercion first.  */
  146.   if (current_language->la_language == language_ada)
  147.     arg = ada_convert_actual (arg, type);

  149.   /* Force the value to the target if we will need its address.  At
  150.      this point, we could allocate arguments on the stack instead of
  151.      calling malloc if we knew that their addresses would not be
  152.      saved by the called function.  */
  153.   arg = value_coerce_to_target (arg);

  155.   switch (TYPE_CODE (type))
  156.     {
  157.     case TYPE_CODE_REF:
  158.       {
  159.         struct value *new_value;

  161.         if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
  162.           return value_cast_pointers (type, arg, 0);

  164.         /* Cast the value to the reference's target type, and then
  165.            convert it back to a reference.  This will issue an error
  166.            if the value was not previously in memory - in some cases
  167.            we should clearly be allowing this, but how?  */
  168.         new_value = value_cast (TYPE_TARGET_TYPE (type), arg);
  169.         new_value = value_ref (new_value);
  170.         return new_value;
  171.       }
  172.     case TYPE_CODE_INT:
  173.     case TYPE_CODE_CHAR:
  174.     case TYPE_CODE_BOOL:
  175.     case TYPE_CODE_ENUM:
  176.       /* If we don't have a prototype, coerce to integer type if necessary.  */
  177.       if (!is_prototyped)
  178.         {
  179.           if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
  180.             type = builtin->builtin_int;
  181.         }
  182.       /* Currently all target ABIs require at least the width of an integer
  183.          type for an argument.  We may have to conditionalize the following
  184.          type coercion for future targets.  */
  185.       if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
  186.         type = builtin->builtin_int;
  187.       break;
  188.     case TYPE_CODE_FLT:
  189.       if (!is_prototyped && coerce_float_to_double_p)
  190.         {
  191.           if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_double))
  192.             type = builtin->builtin_double;
  193.           else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin->builtin_double))
  194.             type = builtin->builtin_long_double;
  195.         }
  196.       break;
  197.     case TYPE_CODE_FUNC:
  198.       type = lookup_pointer_type (type);
  199.       break;
  200.     case TYPE_CODE_ARRAY:
  201.       /* Arrays are coerced to pointers to their first element, unless
  202.          they are vectors, in which case we want to leave them alone,
  203.          because they are passed by value.  */
  204.       if (current_language->c_style_arrays)
  205.         if (!TYPE_VECTOR (type))
  206.           type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
  207.       break;
  208.     case TYPE_CODE_UNDEF:
  209.     case TYPE_CODE_PTR:
  210.     case TYPE_CODE_STRUCT:
  211.     case TYPE_CODE_UNION:
  212.     case TYPE_CODE_VOID:
  213.     case TYPE_CODE_SET:
  214.     case TYPE_CODE_RANGE:
  215.     case TYPE_CODE_STRING:
  216.     case TYPE_CODE_ERROR:
  217.     case TYPE_CODE_MEMBERPTR:
  218.     case TYPE_CODE_METHODPTR:
  219.     case TYPE_CODE_METHOD:
  220.     case TYPE_CODE_COMPLEX:
  221.     default:
  222.       break;
  223.     }

  225.   return value_cast (type, arg);
  226. }

  228. /* Return the return type of a function with its first instruction exactly at
  229.    the PC address.  Return NULL otherwise.  */

  231. static struct type *
  232. ‌find_function_return_type (CORE_ADDR pc)
  233. {
  234.   struct symbol *sym = find_pc_function (pc);

  236.   if (sym != NULL && BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) == pc
  237.       && SYMBOL_TYPE (sym) != NULL)
  238.     return TYPE_TARGET_TYPE (SYMBOL_TYPE (sym));

  240.   return NULL;
  241. }

  243. /* Determine a function's address and its return type from its value.
  244.    Calls error() if the function is not valid for calling.  */

  246. CORE_ADDR
  247. ‌find_function_addr (struct value *function, struct type **retval_type)
  248. {
  249.   struct type *ftype = check_typedef (value_type (function));
  250.   struct gdbarch *gdbarch = get_type_arch (ftype);
  251.   struct type *value_type = NULL;
  252.   /* Initialize it just to avoid a GCC false warning.  */
  253.   CORE_ADDR funaddr = 0;

  255.   /* If it's a member function, just look at the function
  256.      part of it.  */

  258.   /* Determine address to call.  */
  259.   if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
  260.       || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
  261.     funaddr = value_address (function);
  262.   else if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
  263.     {
  264.       funaddr = value_as_address (function);
  265.       ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
  266.       if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
  267.           || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
  268.         funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr,
  269.                                                       &current_target);
  270.     }
  271.   if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
  272.       || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
  273.     {
  274.       value_type = TYPE_TARGET_TYPE (ftype);

  276.       if (TYPE_GNU_IFUNC (ftype))
  277.         {
  278.           funaddr = gnu_ifunc_resolve_addr (gdbarch, funaddr);

  280.           /* Skip querying the function symbol if no RETVAL_TYPE has been
  281.              asked for.  */
  282.           if (retval_type)
  283.             value_type = find_function_return_type (funaddr);
  284.         }
  285.     }
  286.   else if (TYPE_CODE (ftype) == TYPE_CODE_INT)
  287.     {
  288.       /* Handle the case of functions lacking debugging info.
  289.          Their values are characters since their addresses are char.  */
  290.       if (TYPE_LENGTH (ftype) == 1)
  291.         funaddr = value_as_address (value_addr (function));
  292.       else
  293.         {
  294.           /* Handle function descriptors lacking debug info.  */
  295.           int found_descriptor = 0;

  297.           funaddr = 0;        /* pacify "gcc -Werror" */
  298.           if (VALUE_LVAL (function) == lval_memory)
  299.             {
  300.               CORE_ADDR nfunaddr;

  302.               funaddr = value_as_address (value_addr (function));
  303.               nfunaddr = funaddr;
  304.               funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr,
  305.                                                             &current_target);
  306.               if (funaddr != nfunaddr)
  307.                 found_descriptor = 1;
  308.             }
  309.           if (!found_descriptor)
  310.             /* Handle integer used as address of a function.  */
  311.             funaddr = (CORE_ADDR) value_as_long (function);
  312.         }
  313.     }
  314.   else
  315.     error (_("Invalid data type for function to be called."));

  317.   if (retval_type != NULL)
  318.     *retval_type = value_type;
  319.   return funaddr + gdbarch_deprecated_function_start_offset (gdbarch);
  320. }

  322. /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
  323.    function returns to.  */

  325. static CORE_ADDR
  326. ‌push_dummy_code (struct gdbarch *gdbarch,
  327.                  CORE_ADDR sp, CORE_ADDR funaddr,
  328.                  struct value **args, int nargs,
  329.                  struct type *value_type,
  330.                  CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
  331.                  struct regcache *regcache)
  332. {
  333.   gdb_assert (gdbarch_push_dummy_code_p (gdbarch));

  335.   return gdbarch_push_dummy_code (gdbarch, sp, funaddr,
  336.                                   args, nargs, value_type, real_pc, bp_addr,
  337.                                   regcache);
  338. }

  340. /* Fetch the name of the function at FUNADDR.
  341.    This is used in printing an error message for call_function_by_hand.
  342.    BUF is used to print FUNADDR in hex if the function name cannot be
  343.    determined.  It must be large enough to hold formatted result of
  344.    RAW_FUNCTION_ADDRESS_FORMAT.  */

  346. static const char *
  347. ‌get_function_name (CORE_ADDR funaddr, char *buf, int buf_size)
  348. {
  349.   {
  350.     struct symbol *symbol = find_pc_function (funaddr);

  352.     if (symbol)
  353.       return SYMBOL_PRINT_NAME (symbol);
  354.   }

  356.   {
  357.     /* Try the minimal symbols.  */
  358.     struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (funaddr);

  360.     if (msymbol.minsym)
  361.       return MSYMBOL_PRINT_NAME (msymbol.minsym);
  362.   }

  364.   {
  365.     char *tmp = xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT),
  366.                             hex_string (funaddr));

  368.     gdb_assert (strlen (tmp) + 1 <= buf_size);
  369.     strcpy (buf, tmp);
  370.     xfree (tmp);
  371.     return buf;
  372.   }
  373. }

  375. /* Subroutine of call_function_by_hand to simplify it.
  376.    Start up the inferior and wait for it to stop.
  377.    Return the exception if there's an error, or an exception with
  378.    reason >= 0 if there's no error.

  380.    This is done inside a TRY_CATCH so the caller needn't worry about
  381.    thrown errors.  The caller should rethrow if there's an error.  */

  383. static struct gdb_exception
  384. ‌run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc)
  385. {
  386.   volatile struct gdb_exception e;
  387.   int saved_in_infcall = call_thread->control.in_infcall;
  388.   ptid_t call_thread_ptid = call_thread->ptid;
  389.   int saved_sync_execution = sync_execution;

  391.   /* Infcalls run synchronously, in the foreground.  */
  392.   if (target_can_async_p ())
  393.     sync_execution = 1;

  395.   call_thread->control.in_infcall = 1;

  397.   clear_proceed_status (0);

  399.   disable_watchpoints_before_interactive_call_start ();

  401.   /* We want stop_registers, please...  */
  402.   call_thread->control.proceed_to_finish = 1;

  404.   TRY_CATCH (e, RETURN_MASK_ALL)
  405.     {
  406.       int was_sync = sync_execution;

  408.       proceed (real_pc, GDB_SIGNAL_0, 0);

  410.       /* Inferior function calls are always synchronous, even if the
  411.          target supports asynchronous execution.  Do here what
  412.          `proceed' itself does in sync mode.  */
  413.       if (target_can_async_p ())
  414.         {
  415.           wait_for_inferior ();
  416.           normal_stop ();
  417.           /* If GDB was previously in sync execution mode, then ensure
  418.              that it remains so.  normal_stop calls
  419.              async_enable_stdin, so reset it again here.  In other
  420.              cases, stdin will be re-enabled by
  421.              inferior_event_handler, when an exception is thrown.  */
  422.           if (was_sync)
  423.             async_disable_stdin ();
  424.         }
  425.     }

  427.   /* At this point the current thread may have changed.  Refresh
  428.      CALL_THREAD as it could be invalid if its thread has exited.  */
  429.   call_thread = find_thread_ptid (call_thread_ptid);

  431.   enable_watchpoints_after_interactive_call_stop ();

  433.   /* Call breakpoint_auto_delete on the current contents of the bpstat
  434.      of inferior call thread.
  435.      If all error()s out of proceed ended up calling normal_stop
  436.      (and perhaps they should; it already does in the special case
  437.      of error out of resume()), then we wouldn't need this.  */
  438.   if (e.reason < 0)
  439.     {
  440.       if (call_thread != NULL)
  441.         breakpoint_auto_delete (call_thread->control.stop_bpstat);
  442.     }

  444.   if (call_thread != NULL)
  445.     call_thread->control.in_infcall = saved_in_infcall;

  447.   sync_execution = saved_sync_execution;

  449.   return e;
  450. }

  452. /* A cleanup function that calls delete_std_terminate_breakpoint.  */
  453. static void
  454. ‌cleanup_delete_std_terminate_breakpoint (void *ignore)
  455. {
  456.   delete_std_terminate_breakpoint ();
  457. }

  459. /* See infcall.h.  */

  461. struct value *
  462. ‌call_function_by_hand (struct value *function, int nargs, struct value **args)
  463. {
  464.   return call_function_by_hand_dummy (function, nargs, args, NULL, NULL);
  465. }

  467. /* All this stuff with a dummy frame may seem unnecessarily complicated
  468.    (why not just save registers in GDB?).  The purpose of pushing a dummy
  469.    frame which looks just like a real frame is so that if you call a
  470.    function and then hit a breakpoint (get a signal, etc), "backtrace"
  471.    will look right.  Whether the backtrace needs to actually show the
  472.    stack at the time the inferior function was called is debatable, but
  473.    it certainly needs to not display garbage.  So if you are contemplating
  474.    making dummy frames be different from normal frames, consider that.  */

  476. /* Perform a function call in the inferior.
  477.    ARGS is a vector of values of arguments (NARGS of them).
  478.    FUNCTION is a value, the function to be called.
  479.    Returns a value representing what the function returned.
  480.    May fail to return, if a breakpoint or signal is hit
  481.    during the execution of the function.

  483.    ARGS is modified to contain coerced values.  */

  485. struct value *
  486. ‌call_function_by_hand_dummy (struct value *function,
  487.                              int nargs, struct value **args,
  488.                              call_function_by_hand_dummy_dtor_ftype *dummy_dtor,
  489.                              void *dummy_dtor_data)
  490. {
  491.   CORE_ADDR sp;
  492.   struct type *values_type, *target_values_type;
  493.   unsigned char struct_return = 0, hidden_first_param_p = 0;
  494.   CORE_ADDR struct_addr = 0;
  495.   struct infcall_control_state *inf_status;
  496.   struct cleanup *inf_status_cleanup;
  497.   struct infcall_suspend_state *caller_state;
  498.   CORE_ADDR funaddr;
  499.   CORE_ADDR real_pc;
  500.   struct type *ftype = check_typedef (value_type (function));
  501.   CORE_ADDR bp_addr;
  502.   struct frame_id dummy_id;
  503.   struct cleanup *args_cleanup;
  504.   struct frame_info *frame;
  505.   struct gdbarch *gdbarch;
  506.   struct cleanup *terminate_bp_cleanup;
  507.   ptid_t call_thread_ptid;
  508.   struct gdb_exception e;
  509.   char name_buf[RAW_FUNCTION_ADDRESS_SIZE];
  510.   int stack_temporaries = thread_stack_temporaries_enabled_p (inferior_ptid);

  512.   if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
  513.     ftype = check_typedef (TYPE_TARGET_TYPE (ftype));

  515.   if (!target_has_execution)
  516.     noprocess ();

  518.   if (get_traceframe_number () >= 0)
  519.     error (_("May not call functions while looking at trace frames."));

  521.   if (execution_direction == EXEC_REVERSE)
  522.     error (_("Cannot call functions in reverse mode."));

  524.   frame = get_current_frame ();
  525.   gdbarch = get_frame_arch (frame);

  527.   if (!gdbarch_push_dummy_call_p (gdbarch))
  528.     error (_("This target does not support function calls."));

  530.   /* A cleanup for the inferior status.
  531.      This is only needed while we're preparing the inferior function call.  */
  532.   inf_status = save_infcall_control_state ();
  533.   inf_status_cleanup
  534.     = make_cleanup_restore_infcall_control_state (inf_status);

  536.   /* Save the caller's registers and other state associated with the
  537.      inferior itself so that they can be restored once the
  538.      callee returns.  To allow nested calls the registers are (further
  539.      down) pushed onto a dummy frame stack.  Include a cleanup (which
  540.      is tossed once the regcache has been pushed).  */
  541.   caller_state = save_infcall_suspend_state ();
  542.   make_cleanup_restore_infcall_suspend_state (caller_state);

  544.   /* Ensure that the initial SP is correctly aligned.  */
  545.   {
  546.     CORE_ADDR old_sp = get_frame_sp (frame);

  548.     if (gdbarch_frame_align_p (gdbarch))
  549.       {
  550.         sp = gdbarch_frame_align (gdbarch, old_sp);
  551.         /* NOTE: cagney/2003-08-13: Skip the "red zone".  For some
  552.            ABIs, a function can use memory beyond the inner most stack
  553.            address.  AMD64 called that region the "red zone".  Skip at
  554.            least the "red zone" size before allocating any space on
  555.            the stack.  */
  556.         if (gdbarch_inner_than (gdbarch, 1, 2))
  557.           sp -= gdbarch_frame_red_zone_size (gdbarch);
  558.         else
  559.           sp += gdbarch_frame_red_zone_size (gdbarch);
  560.         /* Still aligned?  */
  561.         gdb_assert (sp == gdbarch_frame_align (gdbarch, sp));
  562.         /* NOTE: cagney/2002-09-18:

  564.            On a RISC architecture, a void parameterless generic dummy
  565.            frame (i.e., no parameters, no result) typically does not
  566.            need to push anything the stack and hence can leave SP and
  567.            FP.  Similarly, a frameless (possibly leaf) function does
  568.            not push anything on the stack and, hence, that too can
  569.            leave FP and SP unchanged.  As a consequence, a sequence of
  570.            void parameterless generic dummy frame calls to frameless
  571.            functions will create a sequence of effectively identical
  572.            frames (SP, FP and TOS and PC the same).  This, not
  573.            suprisingly, results in what appears to be a stack in an
  574.            infinite loop --- when GDB tries to find a generic dummy
  575.            frame on the internal dummy frame stack, it will always
  576.            find the first one.

  578.            To avoid this problem, the code below always grows the
  579.            stack.  That way, two dummy frames can never be identical.
  580.            It does burn a few bytes of stack but that is a small price
  581.            to pay :-).  */
  582.         if (sp == old_sp)
  583.           {
  584.             if (gdbarch_inner_than (gdbarch, 1, 2))
  585.               /* Stack grows down.  */
  586.               sp = gdbarch_frame_align (gdbarch, old_sp - 1);
  587.             else
  588.               /* Stack grows up.  */
  589.               sp = gdbarch_frame_align (gdbarch, old_sp + 1);
  590.           }
  591.         /* SP may have underflown address zero here from OLD_SP.  Memory access
  592.            functions will probably fail in such case but that is a target's
  593.            problem.  */
  594.       }
  595.     else
  596.       /* FIXME: cagney/2002-09-18: Hey, you loose!

  598.          Who knows how badly aligned the SP is!

  600.          If the generic dummy frame ends up empty (because nothing is
  601.          pushed) GDB won't be able to correctly perform back traces.
  602.          If a target is having trouble with backtraces, first thing to
  603.          do is add FRAME_ALIGN() to the architecture vector.  If that
  604.          fails, try dummy_id().

  606.          If the ABI specifies a "Red Zone" (see the doco) the code
  607.          below will quietly trash it.  */
  608.       sp = old_sp;

  610.     /* Skip over the stack temporaries that might have been generated during
  611.        the evaluation of an expression.  */
  612.     if (stack_temporaries)
  613.       {
  614.         struct value *lastval;

  616.         lastval = get_last_thread_stack_temporary (inferior_ptid);
  617.         if (lastval != NULL)
  618.           {
  619.             CORE_ADDR lastval_addr = value_address (lastval);

  621.             if (gdbarch_inner_than (gdbarch, 1, 2))
  622.               {
  623.                 gdb_assert (sp >= lastval_addr);
  624.                 sp = lastval_addr;
  625.               }
  626.             else
  627.               {
  628.                 gdb_assert (sp <= lastval_addr);
  629.                 sp = lastval_addr + TYPE_LENGTH (value_type (lastval));
  630.               }

  632.             if (gdbarch_frame_align_p (gdbarch))
  633.               sp = gdbarch_frame_align (gdbarch, sp);
  634.           }
  635.       }
  636.   }

  638.   funaddr = find_function_addr (function, &values_type);
  639.   if (!values_type)
  640.     values_type = builtin_type (gdbarch)->builtin_int;

  642.   CHECK_TYPEDEF (values_type);

  644.   /* Are we returning a value using a structure return (passing a
  645.      hidden argument pointing to storage) or a normal value return?
  646.      There are two cases: language-mandated structure return and
  647.      target ABI structure return.  The variable STRUCT_RETURN only
  648.      describes the latter.  The language version is handled by passing
  649.      the return location as the first parameter to the function,
  650.      even preceding "this".  This is different from the target
  651.      ABI version, which is target-specific; for instance, on ia64
  652.      the first argument is passed in out0 but the hidden structure
  653.      return pointer would normally be passed in r8.  */

  655.   if (gdbarch_return_in_first_hidden_param_p (gdbarch, values_type))
  656.     {
  657.       hidden_first_param_p = 1;

  659.       /* Tell the target specific argument pushing routine not to
  660.          expect a value.  */
  661.       target_values_type = builtin_type (gdbarch)->builtin_void;
  662.     }
  663.   else
  664.     {
  665.       struct_return = using_struct_return (gdbarch, function, values_type);
  666.       target_values_type = values_type;
  667.     }

  669.   observer_notify_inferior_call_pre (inferior_ptid, funaddr);

  671.   /* Determine the location of the breakpoint (and possibly other
  672.      stuff) that the called function will return to.  The SPARC, for a
  673.      function returning a structure or union, needs to make space for
  674.      not just the breakpoint but also an extra word containing the
  675.      size (?) of the structure being passed.  */

  677.   switch (gdbarch_call_dummy_location (gdbarch))
  678.     {
  679.     case ON_STACK:
  680.       {
  681.         const gdb_byte *bp_bytes;
  682.         CORE_ADDR bp_addr_as_address;
  683.         int bp_size;

  685.         /* Be careful BP_ADDR is in inferior PC encoding while
  686.            BP_ADDR_AS_ADDRESS is a plain memory address.  */

  688.         sp = push_dummy_code (gdbarch, sp, funaddr, args, nargs,
  689.                               target_values_type, &real_pc, &bp_addr,
  690.                               get_current_regcache ());

  692.         /* Write a legitimate instruction at the point where the infcall
  693.            breakpoint is going to be inserted.  While this instruction
  694.            is never going to be executed, a user investigating the
  695.            memory from GDB would see this instruction instead of random
  696.            uninitialized bytes.  We chose the breakpoint instruction
  697.            as it may look as the most logical one to the user and also
  698.            valgrind 3.7.0 needs it for proper vgdb inferior calls.

  700.            If software breakpoints are unsupported for this target we
  701.            leave the user visible memory content uninitialized.  */

  703.         bp_addr_as_address = bp_addr;
  704.         bp_bytes = gdbarch_breakpoint_from_pc (gdbarch, &bp_addr_as_address,
  705.                                                &bp_size);
  706.         if (bp_bytes != NULL)
  707.           write_memory (bp_addr_as_address, bp_bytes, bp_size);
  708.       }
  709.       break;
  710.     case AT_ENTRY_POINT:
  711.       {
  712.         CORE_ADDR dummy_addr;

  714.         real_pc = funaddr;
  715.         dummy_addr = entry_point_address ();

  717.         /* A call dummy always consists of just a single breakpoint, so
  718.            its address is the same as the address of the dummy.

  720.            The actual breakpoint is inserted separatly so there is no need to
  721.            write that out.  */
  722.         bp_addr = dummy_addr;
  723.         break;
  724.       }
  725.     default:
  726.       internal_error (__FILE__, __LINE__, _("bad switch"));
  727.     }

  729.   if (nargs < TYPE_NFIELDS (ftype))
  730.     error (_("Too few arguments in function call."));

  732.   {
  733.     int i;

  735.     for (i = nargs - 1; i >= 0; i--)
  736.       {
  737.         int prototyped;
  738.         struct type *param_type;

  740.         /* FIXME drow/2002-05-31: Should just always mark methods as
  741.            prototyped.  Can we respect TYPE_VARARGS?  Probably not.  */
  742.         if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
  743.           prototyped = 1;
  744.         else if (i < TYPE_NFIELDS (ftype))
  745.           prototyped = TYPE_PROTOTYPED (ftype);
  746.         else
  747.           prototyped = 0;

  749.         if (i < TYPE_NFIELDS (ftype))
  750.           param_type = TYPE_FIELD_TYPE (ftype, i);
  751.         else
  752.           param_type = NULL;

  754.         args[i] = value_arg_coerce (gdbarch, args[i],
  755.                                     param_type, prototyped, &sp);

  757.         if (param_type != NULL && language_pass_by_reference (param_type))
  758.           args[i] = value_addr (args[i]);
  759.       }
  760.   }

  762.   /* Reserve space for the return structure to be written on the
  763.      stack, if necessary.  Make certain that the value is correctly
  764.      aligned.

  766.      While evaluating expressions, we reserve space on the stack for
  767.      return values of class type even if the language ABI and the target
  768.      ABI do not require that the return value be passed as a hidden first
  769.      argument.  This is because we want to store the return value as an
  770.      on-stack temporary while the expression is being evaluated.  This
  771.      enables us to have chained function calls in expressions.

  773.      Keeping the return values as on-stack temporaries while the expression
  774.      is being evaluated is OK because the thread is stopped until the
  775.      expression is completely evaluated.  */

  777.   if (struct_return || hidden_first_param_p
  778.       || (stack_temporaries && class_or_union_p (values_type)))
  779.     {
  780.       if (gdbarch_inner_than (gdbarch, 1, 2))
  781.         {
  782.           /* Stack grows downward.  Align STRUCT_ADDR and SP after
  783.              making space for the return value.  */
  784.           sp -= TYPE_LENGTH (values_type);
  785.           if (gdbarch_frame_align_p (gdbarch))
  786.             sp = gdbarch_frame_align (gdbarch, sp);
  787.           struct_addr = sp;
  788.         }
  789.       else
  790.         {
  791.           /* Stack grows upward.  Align the frame, allocate space, and
  792.              then again, re-align the frame???  */
  793.           if (gdbarch_frame_align_p (gdbarch))
  794.             sp = gdbarch_frame_align (gdbarch, sp);
  795.           struct_addr = sp;
  796.           sp += TYPE_LENGTH (values_type);
  797.           if (gdbarch_frame_align_p (gdbarch))
  798.             sp = gdbarch_frame_align (gdbarch, sp);
  799.         }
  800.     }

  802.   if (hidden_first_param_p)
  803.     {
  804.       struct value **new_args;

  806.       /* Add the new argument to the front of the argument list.  */
  807.       new_args = xmalloc (sizeof (struct value *) * (nargs + 1));
  808.       new_args[0] = value_from_pointer (lookup_pointer_type (values_type),
  809.                                         struct_addr);
  810.       memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs);
  811.       args = new_args;
  812.       nargs++;
  813.       args_cleanup = make_cleanup (xfree, args);
  814.     }
  815.   else
  816.     args_cleanup = make_cleanup (null_cleanup, NULL);

  818.   /* Create the dummy stack frame.  Pass in the call dummy address as,
  819.      presumably, the ABI code knows where, in the call dummy, the
  820.      return address should be pointed.  */
  821.   sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (),
  822.                                 bp_addr, nargs, args,
  823.                                 sp, struct_return, struct_addr);

  825.   do_cleanups (args_cleanup);

  827.   /* Set up a frame ID for the dummy frame so we can pass it to
  828.      set_momentary_breakpoint.  We need to give the breakpoint a frame
  829.      ID so that the breakpoint code can correctly re-identify the
  830.      dummy breakpoint.  */
  831.   /* Sanity.  The exact same SP value is returned by PUSH_DUMMY_CALL,
  832.      saved as the dummy-frame TOS, and used by dummy_id to form
  833.      the frame ID's stack address.  */
  834.   dummy_id = frame_id_build (sp, bp_addr);

  836.   /* Create a momentary breakpoint at the return address of the
  837.      inferior.  That way it breaks when it returns.  */

  839.   {
  840.     struct breakpoint *bpt, *longjmp_b;
  841.     struct symtab_and_line sal;

  843.     init_sal (&sal);                /* initialize to zeroes */
  844.     sal.pspace = current_program_space;
  845.     sal.pc = bp_addr;
  846.     sal.section = find_pc_overlay (sal.pc);
  847.     /* Sanity.  The exact same SP value is returned by
  848.        PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
  849.        dummy_id to form the frame ID's stack address.  */
  850.     bpt = set_momentary_breakpoint (gdbarch, sal, dummy_id, bp_call_dummy);

  852.     /* set_momentary_breakpoint invalidates FRAME.  */
  853.     frame = NULL;

  855.     bpt->disposition = disp_del;
  856.     gdb_assert (bpt->related_breakpoint == bpt);

  858.     longjmp_b = set_longjmp_breakpoint_for_call_dummy ();
  859.     if (longjmp_b)
  860.       {
  861.         /* Link BPT into the chain of LONGJMP_B.  */
  862.         bpt->related_breakpoint = longjmp_b;
  863.         while (longjmp_b->related_breakpoint != bpt->related_breakpoint)
  864.           longjmp_b = longjmp_b->related_breakpoint;
  865.         longjmp_b->related_breakpoint = bpt;
  866.       }
  867.   }

  869.   /* Create a breakpoint in std::terminate.
  870.      If a C++ exception is raised in the dummy-frame, and the
  871.      exception handler is (normally, and expected to be) out-of-frame,
  872.      the default C++ handler will (wrongly) be called in an inferior
  873.      function call.  This is wrong, as an exception can be  normally
  874.      and legally handled out-of-frame.  The confines of the dummy frame
  875.      prevent the unwinder from finding the correct handler (or any
  876.      handler, unless it is in-frame).  The default handler calls
  877.      std::terminate.  This will kill the inferior.  Assert that
  878.      terminate should never be called in an inferior function
  879.      call.  Place a momentary breakpoint in the std::terminate function
  880.      and if triggered in the call, rewind.  */
  881.   if (unwind_on_terminating_exception_p)
  882.     set_std_terminate_breakpoint ();

  884.   /* Everything's ready, push all the info needed to restore the
  885.      caller (and identify the dummy-frame) onto the dummy-frame
  886.      stack.  */
  887.   dummy_frame_push (caller_state, &dummy_id, inferior_ptid);
  888.   if (dummy_dtor != NULL)
  889.     register_dummy_frame_dtor (dummy_id, inferior_ptid,
  890.                                dummy_dtor, dummy_dtor_data);

  892.   /* Discard both inf_status and caller_state cleanups.
  893.      From this point on we explicitly restore the associated state
  894.      or discard it.  */
  895.   discard_cleanups (inf_status_cleanup);

  897.   /* Register a clean-up for unwind_on_terminating_exception_breakpoint.  */
  898.   terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint,
  899.                                        NULL);

  901.   /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
  902.      If you're looking to implement asynchronous dummy-frames, then
  903.      just below is the place to chop this function in two..  */

  905.   /* TP is invalid after run_inferior_call returns, so enclose this
  906.      in a block so that it's only in scope during the time it's valid.  */
  907.   {
  908.     struct thread_info *tp = inferior_thread ();

  910.     /* Save this thread's ptid, we need it later but the thread
  911.        may have exited.  */
  912.     call_thread_ptid = tp->ptid;

  914.     /* Run the inferior until it stops.  */

  916.     e = run_inferior_call (tp, real_pc);
  917.   }

  919.   observer_notify_inferior_call_post (call_thread_ptid, funaddr);

  921.   /* Rethrow an error if we got one trying to run the inferior.  */

  923.   if (e.reason < 0)
  924.     {
  925.       const char *name = get_function_name (funaddr,
  926.                                             name_buf, sizeof (name_buf));

  928.       discard_infcall_control_state (inf_status);

  930.       /* We could discard the dummy frame here if the program exited,
  931.          but it will get garbage collected the next time the program is
  932.          run anyway.  */

  934.       switch (e.reason)
  935.         {
  936.         case RETURN_ERROR:
  937.           throw_error (e.error, _("%s\n\
  938. An error occurred while in a function called from GDB.\n\
  939. Evaluation of the expression containing the function\n\
  940. (%s) will be abandoned.\n\
  941. When the function is done executing, GDB will silently stop."),
  942.                        e.message, name);
  943.         case RETURN_QUIT:
  944.         default:
  945.           throw_exception (e);
  946.         }
  947.     }

  949.   /* If the program has exited, or we stopped at a different thread,
  950.      exit and inform the user.  */

  952.   if (! target_has_execution)
  953.     {
  954.       const char *name = get_function_name (funaddr,
  955.                                             name_buf, sizeof (name_buf));

  957.       /* If we try to restore the inferior status,
  958.          we'll crash as the inferior is no longer running.  */
  959.       discard_infcall_control_state (inf_status);

  961.       /* We could discard the dummy frame here given that the program exited,
  962.          but it will get garbage collected the next time the program is
  963.          run anyway.  */

  965.       error (_("The program being debugged exited while in a function "
  966.                "called from GDB.\n"
  967.                "Evaluation of the expression containing the function\n"
  968.                "(%s) will be abandoned."),
  969.              name);
  970.     }

  972.   if (! ptid_equal (call_thread_ptid, inferior_ptid))
  973.     {
  974.       const char *name = get_function_name (funaddr,
  975.                                             name_buf, sizeof (name_buf));

  977.       /* We've switched threads.  This can happen if another thread gets a
  978.          signal or breakpoint while our thread was running.
  979.          There's no point in restoring the inferior status,
  980.          we're in a different thread.  */
  981.       discard_infcall_control_state (inf_status);
  982.       /* Keep the dummy frame record, if the user switches back to the
  983.          thread with the hand-call, we'll need it.  */
  984.       if (stopped_by_random_signal)
  985.         error (_("\
  986. The program received a signal in another thread while\n\
  987. making a function call from GDB.\n\
  988. Evaluation of the expression containing the function\n\
  989. (%s) will be abandoned.\n\
  990. When the function is done executing, GDB will silently stop."),
  991.                name);
  992.       else
  993.         error (_("\
  994. The program stopped in another thread while making a function call from GDB.\n\
  995. Evaluation of the expression containing the function\n\
  996. (%s) will be abandoned.\n\
  997. When the function is done executing, GDB will silently stop."),
  998.                name);
  999.     }

  1001.   if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY)
  1002.     {
  1003.       const char *name = get_function_name (funaddr,
  1004.                                             name_buf, sizeof (name_buf));

  1006.       if (stopped_by_random_signal)
  1007.         {
  1008.           /* We stopped inside the FUNCTION because of a random
  1009.              signal.  Further execution of the FUNCTION is not
  1010.              allowed.  */

  1012.           if (unwind_on_signal_p)
  1013.             {
  1014.               /* The user wants the context restored.  */

  1016.               /* We must get back to the frame we were before the
  1017.                  dummy call.  */
  1018.               dummy_frame_pop (dummy_id, call_thread_ptid);

  1020.               /* We also need to restore inferior status to that before the
  1021.                  dummy call.  */
  1022.               restore_infcall_control_state (inf_status);

  1024.               /* FIXME: Insert a bunch of wrap_here; name can be very
  1025.                  long if it's a C++ name with arguments and stuff.  */
  1026.               error (_("\
  1027. The program being debugged was signaled while in a function called from GDB.\n\
  1028. GDB has restored the context to what it was before the call.\n\
  1029. To change this behavior use \"set unwindonsignal off\".\n\
  1030. Evaluation of the expression containing the function\n\
  1031. (%s) will be abandoned."),
  1032.                      name);
  1033.             }
  1034.           else
  1035.             {
  1036.               /* The user wants to stay in the frame where we stopped
  1037.                  (default).
  1038.                  Discard inferior status, we're not at the same point
  1039.                  we started at.  */
  1040.               discard_infcall_control_state (inf_status);

  1042.               /* FIXME: Insert a bunch of wrap_here; name can be very
  1043.                  long if it's a C++ name with arguments and stuff.  */
  1044.               error (_("\
  1045. The program being debugged was signaled while in a function called from GDB.\n\
  1046. GDB remains in the frame where the signal was received.\n\
  1047. To change this behavior use \"set unwindonsignal on\".\n\
  1048. Evaluation of the expression containing the function\n\
  1049. (%s) will be abandoned.\n\
  1050. When the function is done executing, GDB will silently stop."),
  1051.                      name);
  1052.             }
  1053.         }

  1055.       if (stop_stack_dummy == STOP_STD_TERMINATE)
  1056.         {
  1057.           /* We must get back to the frame we were before the dummy
  1058.              call.  */
  1059.           dummy_frame_pop (dummy_id, call_thread_ptid);

  1061.           /* We also need to restore inferior status to that before
  1062.              the dummy call.  */
  1063.           restore_infcall_control_state (inf_status);

  1065.           error (_("\
  1066. The program being debugged entered a std::terminate call, most likely\n\
  1067. caused by an unhandled C++ exception.  GDB blocked this call in order\n\
  1068. to prevent the program from being terminated, and has restored the\n\
  1069. context to its original state before the call.\n\
  1070. To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
  1071. Evaluation of the expression containing the function (%s)\n\
  1072. will be abandoned."),
  1073.                  name);
  1074.         }
  1075.       else if (stop_stack_dummy == STOP_NONE)
  1076.         {

  1078.           /* We hit a breakpoint inside the FUNCTION.
  1079.              Keep the dummy frame, the user may want to examine its state.
  1080.              Discard inferior status, we're not at the same point
  1081.              we started at.  */
  1082.           discard_infcall_control_state (inf_status);

  1084.           /* The following error message used to say "The expression
  1085.              which contained the function call has been discarded."
  1086.              It is a hard concept to explain in a few words.  Ideally,
  1087.              GDB would be able to resume evaluation of the expression
  1088.              when the function finally is done executing.  Perhaps
  1089.              someday this will be implemented (it would not be easy).  */
  1090.           /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
  1091.              a C++ name with arguments and stuff.  */
  1092.           error (_("\
  1093. The program being debugged stopped while in a function called from GDB.\n\
  1094. Evaluation of the expression containing the function\n\
  1095. (%s) will be abandoned.\n\
  1096. When the function is done executing, GDB will silently stop."),
  1097.                  name);
  1098.         }

  1100.       /* The above code errors out, so ...  */
  1101.       internal_error (__FILE__, __LINE__, _("... should not be here"));
  1102.     }

  1104.   do_cleanups (terminate_bp_cleanup);

  1106.   /* If we get here the called FUNCTION ran to completion,
  1107.      and the dummy frame has already been popped.  */

  1109.   {
  1110.     struct address_space *aspace = get_regcache_aspace (stop_registers);
  1111.     struct regcache *retbuf = regcache_xmalloc (gdbarch, aspace);
  1112.     struct cleanup *retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
  1113.     struct value *retval = NULL;

  1115.     regcache_cpy_no_passthrough (retbuf, stop_registers);

  1117.     /* Inferior call is successful.  Restore the inferior status.
  1118.        At this stage, leave the RETBUF alone.  */
  1119.     restore_infcall_control_state (inf_status);

  1121.     if (TYPE_CODE (values_type) == TYPE_CODE_VOID)
  1122.       retval = allocate_value (values_type);
  1123.     else if (struct_return || hidden_first_param_p)
  1124.       {
  1125.         if (stack_temporaries)
  1126.           {
  1127.             retval = value_from_contents_and_address (values_type, NULL,
  1128.                                                       struct_addr);
  1129.             push_thread_stack_temporary (inferior_ptid, retval);
  1130.           }
  1131.         else
  1132.           {
  1133.             retval = allocate_value (values_type);
  1134.             read_value_memory (retval, 0, 1, struct_addr,
  1135.                                value_contents_raw (retval),
  1136.                                TYPE_LENGTH (values_type));
  1137.           }
  1138.       }
  1139.     else
  1140.       {
  1141.         retval = allocate_value (values_type);
  1142.         gdbarch_return_value (gdbarch, function, values_type,
  1143.                               retbuf, value_contents_raw (retval), NULL);
  1144.         if (stack_temporaries && class_or_union_p (values_type))
  1145.           {
  1146.             /* Values of class type returned in registers are copied onto
  1147.                the stack and their lval_type set to lval_memory.  This is
  1148.                required because further evaluation of the expression
  1149.                could potentially invoke methods on the return value
  1150.                requiring GDB to evaluate the "this" pointer.  To evaluate
  1151.                the this pointer, GDB needs the memory address of the
  1152.                value.  */
  1153.             value_force_lval (retval, struct_addr);
  1154.             push_thread_stack_temporary (inferior_ptid, retval);
  1155.           }
  1156.       }

  1158.     do_cleanups (retbuf_cleanup);

  1160.     gdb_assert (retval);
  1161.     return retval;
  1162.   }
  1163. }


  1166. /* Provide a prototype to silence -Wmissing-prototypes.  */
  1167. void _initialize_infcall (void);

  1169. void
  1170. ‌_initialize_infcall (void)
  1171. {
  1172.   add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
  1173.                            &coerce_float_to_double_p, _("\
  1174. Set coercion of floats to doubles when calling functions."), _("\
  1175. Show coercion of floats to doubles when calling functions"), _("\
  1176. Variables of type float should generally be converted to doubles before\n\
  1177. calling an unprototyped function, and left alone when calling a prototyped\n\
  1178. function.  However, some older debug info formats do not provide enough\n\
  1179. information to determine that a function is prototyped.  If this flag is\n\
  1180. set, GDB will perform the conversion for a function it considers\n\
  1181. unprototyped.\n\
  1182. The default is to perform the conversion.\n"),
  1183.                            NULL,
  1184.                            show_coerce_float_to_double_p,
  1185.                            &setlist, &showlist);

  1187.   add_setshow_boolean_cmd ("unwindonsignal", no_class,
  1188.                            &unwind_on_signal_p, _("\
  1189. Set unwinding of stack if a signal is received while in a call dummy."), _("\
  1190. Show unwinding of stack if a signal is received while in a call dummy."), _("\
  1191. The unwindonsignal lets the user determine what gdb should do if a signal\n\
  1192. is received while in a function called from gdb (call dummy).  If set, gdb\n\
  1193. unwinds the stack and restore the context to what as it was before the call.\n\
  1194. The default is to stop in the frame where the signal was received."),
  1195.                            NULL,
  1196.                            show_unwind_on_signal_p,
  1197.                            &setlist, &showlist);

  1199.   add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
  1200.                            &unwind_on_terminating_exception_p, _("\
  1201. Set unwinding of stack if std::terminate is called while in call dummy."), _("\
  1202. Show unwinding of stack if std::terminate() is called while in a call dummy."),
  1203.                            _("\
  1204. The unwind on terminating exception flag lets the user determine\n\
  1205. what gdb should do if a std::terminate() call is made from the\n\
  1206. default exception handler.  If set, gdb unwinds the stack and restores\n\
  1207. the context to what it was before the call.  If unset, gdb allows the\n\
  1208. std::terminate call to proceed.\n\
  1209. The default is to unwind the frame."),
  1210.                            NULL,
  1211.                            show_unwind_on_terminating_exception_p,
  1212.                            &setlist, &showlist);

  1214. }